Conventional mechanisms for adjusting the position of the cutting edge in wood-planing and finishing machines have such a construction that a cutting tool 41, as shown in FIG. 11, is secured by a bolt 42 to an inclined mounting surface 40a of the knife stock 40 in such a manner as to be slightly tiltable, and that between the cutting tool 41 and the inclined surface 40a there is interposed a wedge-like adjusting member 43 which is slid in the direction of the width of the feeder table to change the tilting angle of the cutting tool 41 and therefore the degree of projection thereof from the feeder table.
Furthermore, in the conventional adjusting mechanism, a guide blade 51 is secured to a cutting blade 61 through a bolt 44, and the cutting blade 61 is directly abutted against the inclined surface 40a of the knife stock 40, with the cutting blade 61 and the guide blade 51 being attached to the knife stock 40 by another bolt 42 which is passed through the cutting blade 61 from the guide blade 51 and screwed into the stock 40.
Generally, it is necessary that a delicate positional relationship be maintained between the cutting blade 61 and the guide blade 51. Specifically, when the cutting blade 61 and guide blade 51 are assembled, the guide blade 51 must be slightly retracted from the cutting blade 61. The degree of this retraction has a great effect on how well the cutting will be performed. A gap 45 is formed between the blades 51 and 61 when they are assembled as shown in FIG. 12. For a fine adjustment of the relative position between these blades, the bolt 44 is tightened to slightly bend the central portion of the guide blade 51 into the gap 45 thereby finely adjusting the position of the cutting edge of the guide blade 51 up or down.
However, the conventional cutter adjusting mechanism with the construction shown in FIG. 11 has the following disadvantage. Since the guide blade 51 is being forced toward the cutting blade 61 by the fixing bolt 42 which secures the cutting tool 41 to the knife stock 40, the relative position between the cutting edges of the blades 51 and 61 which has been accurately set beforehand in securing the guide blade 51 to the cutting blade 61 by the bolt 44 will be disturbed when the fixing bolt 42 is re-tightened to adjust the tilting angle of the tool 41. This is because fastening the bolt 42 causes the central part of the guide blade 51 to further bend into the gap 45, which in turn causes the cutting edge of the guide blade 51 to move upwards.